Titration and Acid-Base Neutralization

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Titration and Acid-Base Neutralization

• Chemistry
• Mrs. Coyle

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Acid Base Neutralization Reaction

• Acid Base ? Water Salt
• Ex HCl NaOH ? H2O NaCl

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Example Stomach antacids
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Titration

• A laboratory method for determining the
  concentration of an unknown acid or base using a
  neutralization reaction.
• A standard solution,(a solution of known
  concentration), is used.

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Equivalence Point

• The point at which there are stoichiometrically
  equivalent amounts of acid and base.
• H OH-

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Buret
Valve
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Titration
Acid with Phenolpthalein
End-Point
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(No Transcript)
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Indicators

• Indicators are chosen, such that they change
  colors at the range of the pH of interest.
• The solution itself at the end-point may be
• Basic, if the reaction involves a strong base and
  a weak acid.
• Neutral, if the reaction involves a strong acid
  and a strong base.
• Acidic, if the reaction involves a strong acid
  and a weak base.

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Methods of Solving Titration Problems

• a) using stoichiometry
• b) using the titration formula aMaVabMbVb.

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Ex. 1

• What is the concentration of HCl if 30.0 mL of
  0.10 M NaOH neutralizes 50.0mL HCl?
• NaOH HCl ? H2O NaCl
• Hint Use aMaVabMbVb
• Ma
• How many moles of HCl were used?
• Hint moles MaVa , but convert the volume to
  L( 50mL0.05L).

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Ex. 2

• A 20.0 mL solution of Sr(OH)2 is neutralized
  after 25.0 mL of standard 0.05 M HCl is added.
  What is the concentration of Sr(OH)2?
• 2 HCl Sr(OH)2 ? 2 H2O SrCl2

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Ex. 3

• How many mL of 0.20 M H3PO4 are needed to
  neutralize 55.0 mL of a 0.10 M solution of NaOH?

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Ex. 4

• What volume of 0.20M Ca(OH)2 will neutralize 45.0
  mL of a 1M solution of HClO3?